Re: argv subscript range uses too many memory

[Han Pingtian <hanpt@xxxxxxxxxxxxxxxxxx>]

On Tue, Nov 20, 2012 at 10:24:15AM -0800, Bart Schaefer wrote:
> So what about the following?  This is still probably incomplete because
> (ARENA_SIZEOF(fheap) >= (size + fheap->used)) seems like the wrong test
> for whether to begin the search at fheap, but I'm curious whether this
> improves the garbage collection behavior.
> 
> Index: Src/mem.c
> ===================================================================
> RCS file: /cvsroot/zsh/zsh/Src/mem.c,v
> retrieving revision 1.20
> diff -u -r1.20 mem.c
> --- Src/mem.c   14 May 2011 17:23:23 -0000      1.20
> +++ Src/mem.c   20 Nov 2012 18:12:41 -0000
> @@ -507,9 +507,11 @@
> 
>      /* find a heap with enough free space */
> 
> -    for (h = ((fheap && ARENA_SIZEOF(fheap) >= (size + fheap->used))
> -             ? fheap : heaps);
> -        h; h = h->next) {
> +    h = (fheap && ARENA_SIZEOF(fheap) >= (size + fheap->used)) ? fheap : heaps;
> +    for (fheap = NULL; h; h = h->next) {
> +       /* track the first heap with free space in fheap */
> +       if (!fheap && h->used < ARENA_SIZEOF(h))
> +           fheap = h;
>         if (ARENA_SIZEOF(h) >= (n = size + h->used)) {
>             void *ret;
> 
> @@ -566,7 +568,8 @@
>             hp->next = h;
>         else
>             heaps = h;
> -       fheap = h;
> +       if (!fheap)
> +           fheap = h;
> 
>         unqueue_signals();
>  #ifdef ZSH_HEAP_DEBUG

I have tried this patch. Looks like with this patch on 5.0, both 

for i in {1..700000}; do true; done

and 

set -- ~/**/*
while ((ARGC>=3))
do
  print -- "${argv[1,3]}"
  shift 3
done

will run very slow, but the memory problem is solved at the
sametime.